Independent suspension systems cooperate with a drive axle assembly to allow each wheel to move vertically without affecting a laterally spaced opposite wheel. An independent suspension system is subjected to many packaging and design constraints. A central carrier assembly drives a pair of wheel drive shafts, which in turn drive a pair of wheels. Suspension components must be packaged around the central carrier assembly and the wheel drive shafts. These suspension components include upper and lower control arms, shock absorbers, and air springs, for example.
It is desirable to provide a spring element, such as an air spring, at a position that is near an axle centerline in order to accommodate large turning angles and to minimize the size and weight of the lower control arm. This configuration is not easily achieved with current control arm designs. One solution utilizes a spring bracket configuration that is integrated into the lower control arm. This configuration is described in U.S. application Ser. No. 11/373,470, filed on Mar. 10, 2006, which claims priority to provisional application Ser. No. 60/663,800 filed on Mar. 21, 2005.
In this example configuration, the lower control arm includes a base portion, a pair of arms extending inwardly from the base portion for attachment to a vehicle chassis or subframe, and a spring bracket portion extending upwardly from the base portion that supports a spring directly over a wheel drive shaft centerline. While this configuration accommodates large turn angles and minimizes weight when compared to traditional designs, packaging space constraints can still be a problem for vehicles having large wheel travel excursions, i.e. large wheel jounce travel. When a wheel experiences large wheel jounce travel, the spring bracket portion is subjected to significant lateral movement. This lateral movement can bring the spring bracket portion, and/or the spring supported on the spring bracket portion, into contact with other vehicle or suspension components, which can adversely affect efficient operation of the independent suspension system or other vehicle systems.
For the above reasons, it would be desirable provide a control arm and spring bracket configuration that can accommodate large turn angles and minimize weight, as well as accommodating large wheel jounce travel.